Graphene/Sulfur@Graphene Composite Structure Material for a Lithium-Sulfur Battery Cathode

Graphene/sulfur@graphene composite structure as a cathode material is synthesized with a facile method. Graphene can provide a more efficient conductive network for sulfur and improve the coulombic efficiency of the battery. On the other hand, it may also show the anchoring effect on sulfur, which reduces the loss of sulfur and improves the cycling performance of the battery. Due to the unique structure, the initial discharge capacity of a battery assembled with this structure could reach 1036 mAh g−1 at 0.1 C, and its reversible capacity of 619 mAh g−1 was retained after 200 cycles with a low fading rate of 0.2% per cycle. The battery could hold a discharge capacity of 501 mAh g−1 after 200 cycles at 0.5 C. Thus, the electrochemical performance improved because of the reduction of sulfur loss through polysulfide accumulation at the cathode.